Field of the Invention
The present invention relates to a color measuring apparatus, and more particularly, to a color measuring apparatus to be mounted in an image forming apparatus.
Description of the Related Art
In image forming apparatus configured to form a color image using an electrophotographic method, a color tone may fluctuate due to problems of instability and reproducibility in color mixture of toners. The color tone may fluctuate not only in the image forming apparatus configured to form the color image using the electrophotographic method but also in image forming apparatus configured to form a color image using an ink jet method and the like.
In the electrophotographic method, particularly depending on a usage environment and a usage frequency, sensitivity of a photosensitive drum, a toner charging amount, and transfer efficiency for a recording material vary for each color. As a result, a color mixture ratio may deviate from a predetermined value, which is liable to adversely affect the color tone. Further, in the printing industry the color tone is required to be reproduced in a higher level.
In order to solve such problems, a small-sized color measuring apparatus to be suitably used in the image forming apparatus is proposed. For example, in Japanese Patent Application Laic-Open No. 2010-277070, a small-sized color measuring apparatus to be suitably used in the color image forming apparatus is proposed.
The color measuring apparatus includes a light source, an optical emitting member configured to guide a light flux passing through the optical emitting member onto a detected object arranged on a detected surface so as to illuminate the detected object, and an optical light guiding member configured to guide the light flux reflected by the detected object onto an optical member.
Further, the optical emitting member is configured to guide the light flux emitted from the light source utilizing refraction at an incident surface and an emitting surface and reflection at a reflection surface. With this, even when a reading position of the detected object fluctuates, fluctuation of the intensity of the light illuminating the detected surface is reduced. In this manner, the optical emitting member with high illumination efficiency is realized.
In the color measuring apparatus described in Japanese Patent Application Laid-Open No. 2010-277070, the optical emitting member and the light source are fixed on an electronic substrate. However, how to position the optical emitting member and the light source is not described. The accuracy of mounting a general electrical component is lower than the accuracy of mounting an optical component. Therefore, only fixing the optical emitting member and the light source, on the electronic substrate is not enough for sufficiently ensuring the accuracy of the relative position between the light source and the optical emitting member, which may degrade the performance of the color measuring apparatus.
When the accuracy of the relative position between the light source and the optical emitting member is degraded, the efficiency of taking in the light flux at the incident surface of the optical emitting member is degraded. As a result, the intensity of the illumination light illuminating the detected surface is degraded.